Portal - RenderMan

Multi-teleportation
class geometryTeleport( string portalSpaces[] = {}; float portalThickness = 0.01 )
{
...
public void displacement( ... )
{
uniform float i;
for( i = 0; i < arraylength( portalSpaces ); i += 1 )
{
// (0,1), (1,0), (2,3), (3,2), ...
string portalSpace1 = portalSpaces[ i ];
string portalSpace2 = portalSpaces[ i + 1 - 2 * mod( i, 2 ) ];
...
}
}
...
}